NM_000642.3:c.1000dupA

Variant names:

• chr1-99874727-T-TA
• rs1553185302
• NM_000642.3:c.1000dupA

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000642.3(AGL):​c.1000dupA​(p.Thr334AsnfsTer7) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,334 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. T334T) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: AGL NM_000642.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 1.60
• Publications: 0 publications found

Genes affected

AGL (HGNC:321): (amylo-alpha-1, 6-glucosidase, 4-alpha-glucanotransferase) This gene encodes the glycogen debrancher enzyme which is involved in glycogen degradation. This enzyme has two independent catalytic activities which occur at different sites on the protein: a 4-alpha-glucotransferase activity and a amylo-1,6-glucosidase activity. Mutations in this gene are associated with glycogen storage disease although a wide range of enzymatic and clinical variability occurs which may be due to tissue-specific alternative splicing. Alternatively spliced transcripts encoding different isoforms have been described. [provided by RefSeq, Jul 2008]

AGL Gene-Disease associations (from GenCC):

• glycogen storage disease III

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Ambry Genetics, Laboratory for Molecular Medicine, Myriad Women’s Health, Orphanet, G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae), Genomics England PanelApp

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-99874727-T-TA is Pathogenic according to our data. Variant chr1-99874727-T-TA is described in ClinVar as Pathogenic. ClinVar VariationId is 521450.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000642.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	AGL	NM_000642.3	MANE Select	c.1000dupA	p.Thr334AsnfsTer7	frameshift	Exon 8 of 34	NP_000633.2
	AGL	NM_000028.3		c.1000dupA	p.Thr334AsnfsTer7	frameshift	Exon 8 of 34	NP_000019.2
	AGL	NM_000643.3		c.1000dupA	p.Thr334AsnfsTer7	frameshift	Exon 8 of 34	NP_000634.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	AGL	ENST00000361915.8	TSL:1 MANE Select	c.1000dupA	p.Thr334AsnfsTer7	frameshift	Exon 8 of 34	ENSP00000355106.3
	AGL	ENST00000294724.8	TSL:1	c.1000dupA	p.Thr334AsnfsTer7	frameshift	Exon 8 of 34	ENSP00000294724.4
	AGL	ENST00000370163.7	TSL:1	c.1000dupA	p.Thr334AsnfsTer7	frameshift	Exon 8 of 34	ENSP00000359182.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461334 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 726994

African (AFR) AF: 0.00 AC: 0 AN: 33462

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26122

East Asian (EAS) AF: 0.00 AC: 0 AN: 39656

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111574

Other (OTH) AF: 0.00 AC: 0 AN: 60376

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Glycogen storage disease type III Pathogenic:2

Apr 11, 2023

Genome-Nilou Lab

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Sep 02, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Thr334Asnfs*7) in the AGL gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in AGL are known to be pathogenic (PMID: 19299494). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with AGL-related conditions. ClinVar contains an entry for this variant (Variation ID: 521450). For these reasons, this variant has been classified as Pathogenic.

Inborn genetic diseases Pathogenic:1

Jan 30, 2017

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		1.6
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1553185302; hg19: chr1-100340283;